[FONT=&amp]A 30-year-old woman presents with hypertension, weakness, bone pain, and a serum calcium level of 15.2 mg/dL. Hand films below show osteitis fibrosa cystica. Which of the following is the most likely cause of these findings?[/FONT]

[FONT=&amp]EXPLANATION: [/FONT]
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Osteitis fibrosa cystica is a condition associated with hyperparathyroidism that is characterized by severe demineralization with subperiosteal bone resorption (most prominent in the middle phalanx of the second and third fingers), bone cysts, and tufting of the distal phalanges on hand films. These specific bone findings would not be present in sarcoidosis, Paget disease, or metastatic carcinoma. [/FONT]
[FONT=&amp]Vitamin D deficiency can lead to osteitis fibrosa cystica but it would also be associated with hypocalcemia, not hypercalcemia.[/FONT]

[FONT=&amp]EXPLANATION: [/FONT]
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The patient described is exhibiting classic signs and symptoms of hyperparathyroidism. In addition, if a history is obtainable, frequently the patient will relate a history of renal calculi and bone pain—the syndrome characterized as "groans, stones, and bones."[/FONT]

[FONT=&amp]Acute management of the hypercalcemic state includes vigorous hydration to restore intravascular volume, which is invariably diminished. This will establish renal perfusion and thus promote urinary calcium excretion. [/FONT]
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Thiazide diuretics are contraindicated because they frequently cause patients to become hypercalcemic. Instead, diuresis should be promoted with the use of loop diuretics such as furosemide (Lasix). [/FONT]
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The use of intravenous phosphorus infusion is no longer recommended because precipitation in the lungs, heart, or kidney can lead to serious morbidity. [/FONT]
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Mithramycin is an antineoplastic agent that in low doses inhibits bone resorption and thus diminishes serum calcium levels; it is used only when other maneuvers fail to decrease the calcium level. [/FONT]
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Calcitonin is useful at times. [/FONT]
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Bisphosphonates are used for lowering calcium levels in resistant cases, such as those associated with humoral malignancy. [/FONT]
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Emergency neck exploration is seldom warranted. In unprepared patients, the morbidity is unacceptably high.[/FONT]

[FONT=&amp]The answer is A.[/FONT]

A few Xtra thoughts

Broad differentials for Osteomalacia

Inadequate dietary intake of Calcium and Vit D ( remember vit d is fat soluble and with all the focus on reducing fat in diet, the fat soluble vitamin def. ( A & D ) is becoming more prelavent.

Malabsorption - think of 1)Celiac disease ( severe celiac disease will present in chilhood, but mild ones can present in adulthood as the intestinal atrophy cumulates and adds up with the decreases absorption capacity with age....in such cases eliminating gluten should help )
2) Pancreatic insufficiency
3) Giardia infection ( think about it in people who have gone for pilgrimage or hiking and have drank water from unsafe sources....often not asked )
4) these days foods with butter substitutes may have methylcellulose ( as the substitute ) ...this stuff is used to stick wall papers, imagine what it can do to the intestine
5) certain high fiber foods are high in tannins and can coat the intestine...leading to malabsorption

primary hyperparathyrodism - there is a propsed mechanism in Guyton Physiology as to why prim parathyroidism ( adenoma ) or hyperplasia is more common in women...many endocrine glands enlarge during pregnancy...in the case of parathyroid gland it hypertrophies to make more calcium available to the growing fetus and if the pregnancies are closely spaced or high in number ( high birth rates )...then the parathyroid gland may not switch off as it normally should ( leading to wierd things...u know what i mean )...similar mechanism with Prolactinomas.
Secondary hyperparathyroidism

TUmor induced osteomalacia

What does Osteitis Fibrosa cystica mean ?

Osteitis Fibrosa Cystica is a skeletal disorder caused by a surplus of parathyroid hormone from over-active parathyroid glands. This surplus stimulates the activity of osteoclasts, cells that break down bone, in a process known as osteoclastic bone resorption. The over-activity of the parathyroid glands (hyperparathyroidism) can be triggered by parathyroid adenoma, hereditary factors, parathyroid carcinoma, or renal osteodystrophy.

Final thoughts - Atleast some of the cases of Osteoporosis / Decreased bone density that does not respond to the ususal doses of cal and vit d supplementation could be becos of prim hyperparathroidism ( esp. in females ). So do ask for iPTH ( intact Parathyroid not total ) hormone levels...don't be fooled by cal in the normal range

and also think about he various malabsorption problems in your differentials.